Hiterto, the wicks for a burner using liquid fuel as energy sources have been made from a glass fiber, cotton fiber, or a mixed yarn of both. The Japanese utility model, Laid-open No. 52-157535 disclosed liquid fuel combustion wicks which composed of a combustion portion made from glass fiber, fuel absorption and transfer portion made from cotton or cotton staple fiber and the lower fuel oil immersed portion made from propylene resins. Korean utility model publication No. 85-1822 disclosed a wick made from the blended yarn of glass fiber and cotton fiber, whose combustion characteristics are improved by carbonizing the glass fiber in the combustion portion at high temperature, but at a temperature below the melting point of the glass fiber. The prior art described above contributed to the improvement of conventional wicks with respect to a decrease in smoke and carbon black and resulted in an increase in the combustion efficiency. However, combustion remained incomplete and the problems related thereto, such as the production of harmful gas, smoke, nuisance, and odor still remained.
The Korean patent application No. 84-1268, which was granted to the present inventor, teaches novel ceramic wicks for kerosene fuel burners in which the wick itself does not burn during the combustion. This disclosure opened an entirely new approach to the wick. As the wicks were made from artifical ceramics, mechanical and chemical wear of the wick was reduced to a minumum and the life span of the wicks was extended to semi-permanent. Furthermore, this wick contributed the reduction of smoke caused by incomplete combustion, and facilitated the realization of the economy of the fuel. In this prior art, a process is disclosed for preparing ceramic wicks for kerosene burners which comprised the steps of mixing the powder of portland cement with clay; heat treating the mixture at an elevated temperature; re-mixing the mixture thus obtained with charcoal powder and water to produce a paste; and, then, heat treating the mixture at high temperature. The charcoal powder provides an internal pore structure by which the liquid fuel may be transferred by capillary action, and plays a primary role in determining the absorption and transfer rate of the wick. But there are problems, such as the difficulties in handling charcoal powder, in mixing of the charcoal with water during the preparation stage, and in the unevenness and reduction of the pore space in the resulting ceramic wick.